Oh yeah, that's why I originally used plastic with unibond. I couldn't remember why I was wrapping in plastic, so when I switched to weldwood I didn't wrap, and I didn't have any problems with the bow sticking to the form, but I can see if happening.
After re-reading the spec sheet it says "pre-catalyzed water-activated glue". So the water starts the chemical reaction, so it shouldn't have any problems drying with plastic.